In November 2015, IDC projected that worldwide HDD shipments for 4Q15 would be 117.5 million units (see Worldwide 3Q15 HDD Shipment Results and Four-Quarter Forecast Update, IDC #US40614615, November 2015).

IDC's preliminary 4Q15 worldwide HDD shipment results indicate that the HDD industry shipped between 114.9 million units and 117.3 million units in the quarter, equating to approximately 138,000PB shipped in 4Q15, representing a 2.0% increase quarter over quarter, but down by 5.0% year over year.

HDD unit shipments for enterprise applications were slightly weaker in 4Q15 than IDC had expected and were relatively flat from 3Q15 to 4Q15. However, enterprise HDD petabyte shipments for enterprise applications did increase sequentially in 4Q15 as the demand for capacity-optimized HDDs used in enterprise datacenters continues to mix up to higher-capacity HDD products.

Worldwide HDD shipments for CY15 declined by approximately 16.7% year over year. However HDD petabyte shipments were relatively flat from CY14 to CY15. IDC expects that worldwide HDD shipments will decline again slightly in CY16, but HDD petabyte shipments should increase by approximately 17% year over year as customer demand continues to shift to higher-capacity HDDs, especially for HDDs used in enterprise applications.